Ore treatment



Patented July 21,

uurrsn STATES PATENT oFFicn.

VIRGIL MILLER, 01? SALT LAKE CITY, AND HENRY DUKE BALLOW, OF LEVAN, UTAH,

can TREATMENT.

1N0 Drawing.

To all whom it may concern:

Be it known that we, (1) VIRGIL MILLER, and (2) HENRY DUKE BALLow, citizens of the United States, residing at (1) Salt Lake City, (2) Levan, in the county of (1) Salt Lake (2) Juab County, and State of (1) Utah (2) Utah, have invented certain new and useful Improvements in Ore Treatment, of which the following; is a specification.

This invention relates to a process for the separation or partial separation or concentration of the constituents of ores or analogous mixtures or materials and more particularly to a treatment of carbonate ores or analogous mixtures or materials containing a metal carbonate such as lead carbonate intermixed or associated with other materials such as other minerals and gangrue matter preliminary and preparatory to the separation or concentration of the constituents by known methods and involves the decomposition of the metal carbonate by heat, whereby the specific gravity of this constituent is increased and it is rendered separable from the other constituents.

The invention is particularly applicable to ores containing a metal carbonate, such as lead carbonate, associated with materials such as zinc minerals and will be described and illustrated in connection therewith, it being understood however that the invention is not limited to the treatment of any specific material excepting as may be required by the appended claims.

The process of our invention has been found to be of particular value for the treatment of many deposits of oxidized lead-zinc ores found in the western part of the United States in which the lead occurs as the carbonate and zinc is present as the silicate, and also for the treatment of tailingrs con taining lead carbonate which have been dis carded after the separation therefrom of the other metallic values, for instance sulfids. In addition, the process has been found to be applicable'with advantage to certain low grade lead carbonate ores usual- 1y containing silver, and also to some ores which contain a mixture of oxidized constituents and sulfide mineral constituents. In this connection it is noted that the known oxidizing; treatments such as that involved in the Horwood process form no part of the present invention which, although some oxidation may occur incidentally, involves Applica ion filed No ember 29, 1924;. Serial No. 752.9%.

mainly a simple heat treatment of already oxidized constituents.

The process of our invention comprises the following principal steps:

1. Heating;

2-. Cooling the material while preserving the condition produced by the heating operation; and

3. Concentration.

An ore, by which We mean a natural ore or a mixture of materials prepared artificially such as tailings and plant by-prodnets, and containing for instance lead oarbonate and other minerals or gangue matter such as zinc silicate, is heated in any suitable furnace to a temperature above 17 5 C. The decomposition of the lead carbonate with the formation of lead oxid takes place rather slowly at 175 C. and more rapidly at high temperatures, being very rapid at 400 C. The best temperature to be used in any particular case depends to some extent upon the properties of the material under treatment, but usually lies between 175 and 400 (1, preferably around 300 0., although under some conditions it is found advantageous to operate at higher temperatures, Under ordinary conditions, and without any special precautions as to cooling, both the red and yellow oxids of lead are present. The yellow oxid has the higher specific gravity and the keeping of the lead in this form is promoted by sudden rather than by slow cooling.

The hot ore is then cooled under such conditions as to preserve the best conditions produced by the heating operation, for instance by quickly quenching it with water after the desired condition has been reached.

The ore so prepared then suitable for concentration.

The conversion of the lead carbonate to lead oxid or oxids produces an increase in the specific gravity of the lead content of the ore while in general the other components, for instance gangue matter or zinc silicate in the specific instance referred to, remain unchanged and the gravity separation of the lead from the other constituents of the ore is thus facilitated.

Tests of the process made upon natural carbonate ores of lead and zinc have given surprisingly good separations.

The process, as is apparent, is very simple and inexpensive and is therefore economically applicable to poor grades of ore and to tailings heretofore-regarded as Waste or valueless material;

We claim 1.v Process for the concentration of the lead values of'oxidized ores which comprises heating the ore to a temperature suflicient to convert the read carbonate content of the ore to lead oXid and thereafter subjecting the ore to gravity separation.

2. Process for the treatment of ores containing lead carbonate comprising heating the ore at a ten'iperatu ro above 175 C. until the lead carbonate is converted to an oxid of lead and thereaiter sub ecting the ore to a gravity separation.

3. Process for the treatment 01 lead-zinc ores containing lead carbonate and zinc sili cate- Which comprises heating the ore to a temperature suflicient to convert the load carbonate to an oXid of lead but below that at Which lead silicate forms and thereafter subjecting the ore to a gravity separation.

4. Process for the treatment of ores containing lead caroonate and zinc silicate Whichcomprises heating the ore to a temperature of from 175 to 400 C. until the lead carbonate is converted to an oxid of lead and thereafter subjecting the ore to a gravity separation.

In testimony whereof, We aliix our signatures.

VIRGIL MILLER. HENRY DUKE BALLOW. 

